In recent years, organic electro luminescence (EL) displays using organic EL have attracted attention as candidates for next-generation flat-panel displays to replace liquid crystal displays. An active-matrix display device, such as the organic EL display, includes a thin-film transistor (TFT) as a drive transistor.
Silicon is often used for the semiconductor layer (channel layer) of the thin-film transistor, but recently a thin-film transistor has been developed which uses an oxide semiconductor, as represented by amorphous IGZO (In—Ga—Zn—O), for the semiconductor layer (see Patent Literature (PTL) 1, for example).